The present invention relates to a method and apparatus for the alignment and extraction of a sample of the fibers of a fabric or other material for fiber length measurement, and more particularly for the extraction of a fiber sample from a sliver of material having parallelized fibers by the removal of a sample of the fiber ends of the sliver while the sliver is in a stretched position.
In order to inspect fibers having a finite length, a length measurement of the fiber is carried out whereby a representative value for the complete fiber mass is obtained. This is called a staple measurement. In obtaining such a staple measurement, particular care must be taken when extracting the sample.
In carrying out such staple measurment on textile fibers, the fiber is first prepared by forming a parallelized sliver from the material to be tested and the fiber sample is extracted from the end of the sliver maintained in end aligned manner. The fiber length in the sample is then measured, for example, capacitatively or optically, to determine the stable diagram, which is a representation of the population of the fibers arranged in accord with fiber length. The information content obtained from a fiber sample with unaligned ends is much smaller than that obtained from an end aligned sample.
The objects of the invention are to provide a method and apparatus for properly aligning the fiber ends during extraction of the sample and also to provide a fiber sample extraction method and apparatus that has greater precision, better reproducibility, reduced susceptibility to dirtying, better guidance of the fibers and better operational reliability as compared with previously known methods and apparatus.